Tuyere block



Jan. 26, 1932. c. H. RICH 1,843,000

TUYERE BLOCK Filed July 9 92 INVENTOR CARL H. R1011 ATT NEY I WITNESS between the blocks,-

Patentecl Jan, 26, 1932" UNITED STATES PATENT OFFICE CARL E. RICH, 0F WORCESTER,

MASSACHUSETTS, ASSIGNOR T0 RILEY STOKER COR- TUYERE BLOCK This invention relates to tuyere blocks, and more particularly to tuyere blocks as used in connection with automatic stokers.

In certain types of automatic stokers, it is customary to arrange tuyere blocks to form a support for the fuel bed and supply air thereto, and they are subjected to extreme heat from the fire above. Such a tuyere block is usually of cast iron, and the excessive heat causes it to expand and grow, gradually becoming permanently enlarged. This heat is moreover applied mainly at the exposed end of the block. As a result, the tuyere block as heretofore constructed has been subjected to enormous internal strains caused by the uneven expansion. Cracks have appeared,

. causing fragments to drop off, thus exposing large air openings, and rendering the block useless as a support for the fuel. Such rapid deteriorationin the past has been the cause of large expense and frequent shut downs of the furnace. r v

In stokers having blocks piled or arranged closely adjacent to each other, it is often found that there is not sufiicientroom for expansion so that they crowd each other at certain points and open up passages at other points, or otherwise cause improper actionlofthe furnace. This defect is particularly noticeable in a stoker of the type in which two sets of tuyere blocks are mounted for relative reciproca'tory movement on the side walls of adjacent retorts. As the growth takes place mainly at the exposed end ofthe block, this has forced the sidewalls apart, causing themto bind, and opening up large spaces through which siftings would fall;

It is, accordingly the main object of my inventionto overcome such difliculties and to provide a tuyere. block construction which permits expansion under the influence of the extreme heat to which it is necessarily subjected without the setting up of detrimental internal strains and the consequent breakage or warpage of the block.

A further object of my invention is to provide, for underfeed moving retort side stokers having relatively to increase in size laterally without forcing size.

' expansion between the blocks'in walls, tuyere blocks whichmay be carried on the walls and will be free Application filed July e, 1926. Serial No. 121,465.

the walls apart or otherwise seriously affecting the operation of the stoker.

A further object is to provide a tuyre block fuel bed, and which will maintain this efliciency throughout a long life before requiring replacement. a

With these and other objects in view as will be apparent to one skilled in the art, my invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

According to my invention, I provide a tuyere block with a portion cut away at that part of the block which is subjected to the greatest heat, and which is so arranged that the block is free to expand into the cutaway portions without causing serious internal strains. One form of block,arranged to be piled in a steplike formation, may comprise an approximately horizontal web portion, provided with a grooved surface and having slots cut through the web, thus permitting the block to expand inwardly or increase in The grooved surface may be sov arranged as to form tuyere openings or air passages, and to direct the-air in a desired manner into the fuel bed. In applying my improved tuyere block to stokers having relatively movable retort side walls,'I may so construct the blocks that they will slope away,

at the ends exposed to the heat, from the dividing line between the retorts. In this way, a block is free to expand without crowding against the laterally adjacent block. Also, if desired, pace may be provided for a single tier, as by sloping the bottom of a block at its nose portion to permit vertical growth of the noses of the blocks.

Referring 'to the drawings, in which like reference numerals indicate like parts:

Fig. 1 is a perspective view of one of m improved tuyre blocks, as constructed for a stoker having relatively moving retort side 9 walls;

Fig.2 is a bottom plan view on a reduced scale of the block shown in Fig. 1;

Fig. 3 is a top plan View of several of which will admit air efficiently to the these blocks assembled in their proper relative positions;

Fig. 4 is a side elevation of the blocks as arranged in Fig. 3;

Fig. 5 is a diagrammatical cross section showing tuyere blocks mounted on the retort side walls of an underfeed Stoker; and

Fig. 6 illustrates diagrammatically an arrangement of tuyere blocks which have upwardly sloping bottoms.

The embodiment of my invention illustrated in the drawings comprises a tuyere block adapted for use on stokers of the type shown in the patent to Riley No. 1,322,822. In such a stoker, as shown in Fig. 5, two sets of tuyere blocks 1 and 2 may be mounted on the opposed side walls 3 and 4 of adjacent retorts of an underfeed stoker. These side walls are arranged to be reciprocated relative to each other by suitable mechanism. As shown in Fig. 3, the adjacent faces of the two sets of blocks are arranged close to each other for such reciprocative movement, and they are provided with tuyere passages 5 which communicate at their inner covered ends with the air trunk 6 beneath the blocks and between the side walls 3 and 4 of the retorts. The retort bottoms 7 are stationary, and the sifting of fine coal between them and the side walls is prevented by siftings strips 8. The blocks are superimposed on one another in a steplike formation, each having a nose exposed directly to radiant heat and a portion covered by the block above which is cooled by the air fed thereto, this arrangement being such as to produce radically different conditions at the opposite ends of each block which often result in uneven expansion of the different parts and a permanent growth of the exposed nose portion.

To overcome this difliculty, I provide a block which may grow permanently without detrimental effect on either itself or the neighbouring blocks and so give a longer life of useful service. One form of block, as illustrated, maybe constructed with a substantially horizontal web portion 10, which is preferably well rounded off on the outside corner of the nose where exposed to the heat.

This is'desirable in order to avoid the exces-- sive burning of the block which would take place if a sharp corner projected into the fuel bed. Each tuyere block is preferably provided with a grooved surface to form tuyere openings and to hold ashes thereon, as well as to aid in cooling the block. The grooved surface may be formed by means of ribs projecting from the central web portion. As shown, the upper face of the web 10 has four vertical ribs 11, 12, 14 and 16. vOn the lower surfaceof the web portion I have shown seven ribs 18 to 24 inclusive. These lower ribs are directed at various angles, as illustrated, so as to distribute the air from a central space 25 into the fuel bed. The ribs on the upper surface preferably slope downwardly as they approach the edge of the web, so as to avoid sharp corners which would project upwardly into the fuel. Ribs 11 and 14 are made comparatively short so as to avoid interference with ribs 18 and 19 respectively on the superimposed block, when the parts are assembled. as shown in Fig. 3. Ribs 12 and 16 are made comparatively long, and are so arranged as to extend between ribs 18 and 19, and 19 and 20 respectively on the superimposed block. A depending flange 26 is novidcd on the bottom and along the side 0 the block to form a continuation of rib 24, and

thereby prevent the escape of air at this point. A slightly raised lug 27 (Fig. 3) projects laterally from the rib 12 and is so arranged as to fit against the side of the rib 18 on the superimposed block. The two ribs 18 of adjacent blocks fit in the space between the two lugs 27 on the lower blocks, whereby the blocks are properly positioned. Downwardly detial features of this invention.

As shown in Fig. 3, the blocks are so arranged that only the nose portion of each block is exposed to the intense heat from the fuel bed above. In order to provide room for permanent growth of the block and thus eliminate internal strains and the resulting cracks, I may form cutaway portions in the nose portion of the web 10. These cutaway portions preferably extend entirely throueglh the web as slots 35 and 36 so as to give e blocks ample room and freedom for growth inwardly. These slots may be located between the upper ribs 11 and 12 and ribs 12 and 14. They preferably are so placed as to come directly over ribs 12 and 16 on the blocl beneath, thus to a certain extent preventing the escape of air upwardly through the slots.

If desired,the slots may be filled with a refractory substance, such as a. suitable clay, which will prevent the escape of air therethrough and yet be sufficiently yielding as to permit expansion of the metal.

It has been found in the past that grate blocks tend to expand laterally at that porwalls 11 and 18 of the blocks away from each other at the portions exposed to the heat, thus forming a wedge shaped space 40 into which each block is free to expand without crowding the adjacent block'. This space 40 does not permit siftings to drop through, as the opening is covered by the web of the block beneath, as shown in Fig. 3.

In Fig. 6 I have illustrated diagramm-atically a modified form of my invention. Tuyere blocks 45 are arranged in steplike formation, and the bottom of each block is sloped upwardly, thus providing a space 46 into which the exposed nose of the block may expand-without crowding the block beneath.

It will evident to those skilled in the art that I have provided a tuyere block in which the slots as shown entirely eliminate the formation of cracks and thebreaking off of parts of the block and the consequentexposure of large openings, because they provide spaces into which the block may grow freely when exposed to the excessive heat of a furnace as well as the severe physical and chemical conditions to which such blocks must be subjected. When assembled as by bolting the blocks on a supporting side bar, the ribs on the superimposed blocks form long narrow tuyere passages running from the, central space 25 to the outer edges of the blocks. This space 25, as is understood, opens to the air chamber 6 beneath and between the retorts. The ribs serve not only to separate the webs 10 and 'form tuyeres but to strengthen the block and to provide radiating surfaces of large extent which transfer the heat from the block to the entering air, thus preheating the air and cooling the block. It will be apparent that the cutaway portions or slots may be variously located and made in suitable sizes and numbers to carry out the purposes of this invention, and that various types of tuyere and grate blocks used in stokers may be constructed in accordance with my invention.

Having-thus described my invention, what I claim as new and desire to secure by Lettcl's Patent'is:

1. An underfeed stoker having relatively reciprocable side walls forming retorts, one wall of each retort being parallel and adjacent to the wall of an adjoining retort and independent sets of tuyere blocks mounted on said relatively movable walls, the laterally adjacent tuyere blocks having their adjacent faces sloping away from each other throughout their heat exposed portions to provide a space into which said steplike formation on each of said reciproblocks may expand laterally without crowding.

downwardly to form tuyere openings between i said plate and the plate beneath, said ribs being spaced apart at their rear ends for the introduction of air to'the tuyere openings, and ribs on the .top of the plate which are to contact with the fuel bed, said plate having elongated slots between and substantially parallel with two sets of ribs on opposite sides of the plate which extend inwardly from the vedge of the plate for a sufiicient distance to permit inward portion thereof.

4' A stoker tuyere structure comprising substantially horizontal plates piled in a steplike spaced relation to permit air to flow therebetween to the fuel bed, each plate having a slot extending inwardly from the growth of the heat exposed edge to permit growth thereof, and means to obstruct the flow of air vertically through the slot of the adjacent superposed plate.

5. A stoker comprising a set of tuyere blocks having plates grooved on their under sides which are piled in a step-like formation to permit air to flow therebetween, said plates having slots extending inwardly from their edges to permit growth thereof, the slots being located above projecting portions of the plates below which prevent the escape of air vertically through the slots.

6. A tuyere block for a stoker comprising a tion with other blocks, said plate having ribs on the upper side thereof, which serve to space the plate fromthe one above and form tuyeres, and a slot extending vertically through the plate and inwardly from the normally heat exposed edge for a sufficient distance to permit growth of the plate, one rib on the plate being shaped and located in such a position relative to the slot on a plate above as to underlie the same and prevent the. passage of air therethrough. j

7. A stolrer comprising two sets of tuyere plate adapted to be piled in a step-like formablocks mounted side by side in a step-like formation to support fuel and introduce air thereto, each block having ribs providing air admitting grooves between the blocks, the unexposed portions of laterally adjacent blocks having contacting and substantially parallel sides, and the sides of the portions exposed to direct beveled and sloping away from each other heat radiation being.

at a slight angle to permit lateral growth throughout said exposed portions.

8. A stoker comprising a plurality of tuyre blocks mounted in step-like formation with their nose portions exposed to the heat and provided with grooves for admitting air to a fuel bed supported thereon, the adjacent faces of the blocks being in contact in the unexposed portions thereof and sloping away from each other throughout their heat exposed portions to perrnlt growth under the influence of the heat without crowding.

9. A tuyere block for a stoker comprising a plate having a portion adapted to contact with a fuel bedand be exposed to the heat thereof, and a series of ribs integral with the plateand extending away from the heat exposed edge thereof, said ribs being spaced apart to provide channels for the flow of air to the fuel bed, said plate having an elongated slot which extends through the plate between two of the ribs and away from the heat exposed edge for a considerable distance to permit inward growth of the heat exposed portion, the ribs serving to strengthen the plate adjacent to the slot.

Signed at Worcester, Mass, this 7th day of July, 1926.

CARL H. RICH. 

